Background: After patients suffer from traumatic injuries, the clotting mechanism in the blood is accelerated, but the mechanism involved in this acceleration is not clearly understood. The goal of this proposal titled, Microvesicle production after acute trauma and its clinical impact on venothromboembolism, is to investigate the role of sub-cellular particles that are released by injured tissue. It is believed that these particles, called microvesicles, are released from tissue such as white blood cells and platelets during infection, injury and cell death. On their surface, the microvesicles carry a cargo of clotting enzymes and cell membrane components thought to be important in clot generation. By gaining a better understanding of their role in clotting after injury, we can begin to look for ways to identify patients who may have high amount of microvesicles in their blood and to see if they are more prone to clotting such as deep leg clots (also known as deep vein thrombosis) or clots lodged in the lung (also known as pulmonary embolism), collectively known as venous thromboembolism. In the United States alone, there are over 900,000 cases per year of deep vein thrombosis and pulmonary embolism in hospitalized patients. Trauma patients are especially at high risk of developing these complications. The immediate goal of the proposed research is to be able to identify those trauma patients, based on their physical characteristics (such as age, sex, injury severity) and their blood clotting physiology (such as type and number of microvesicles found in the blood after trauma). Proposed Research: It has two components. The first component will be an extensive review of the medical records of trauma patients who suffered from deep vein thrombosis and pulmonary embolism in Olmsted County, Minnesota (1996-2005). We will study their physical characteristics and assess which are important risk factors for clotting. The second research component is an observational study involving the measurement of microvesicle clotting potential in trauma patients who develop venous thromboembolism. This study will create several opportunities for the applicant. A risk/assessment model will be generated from the proposed research. Ultimately, this information will allow us to better target aggressive therapy early to those assessed to be at high-risk of the morbid hospital complication of venous thromboembolism. Applicant: The applicant is a Trauma/Critical Care Surgeon at the Mayo Clinic in Rochester MN, who is applying for a Mentored Career Development Award. This award entails a research and a career development plan; the receipt of this award will give the applicant protected time to focus on her research objectives and in obtaining a Masters in Biomedical Science Degree. The long-term research goal of the applicant is for her to be an independent physician-scientist with the tools and skills needed to continue her clinical studies that will have a positive impact on the outcome of trauma patients.